Matilija Dam Ecosystem Restoration

Matilija Dam c. 2009

The Matilija Dam is obsolete. Instead of storing water, it is storing sediments that would normally replenish our beaches. In addition, the endangered Southern Steelhead Trout has been unable to access historic prime breeding areas for over 50 years.

The question is not “Will the dam come down?” Its condition makes that a certainty; the dam will come down, sooner or later. Our goal is to bring it down quickly, safely, and in a manner that is good for the river, the community, and the beaches. Our vision is a beautifully restored Matilija Canyon.

Ventura County Surfrider is a member of The Matilija Coalition, the primary community advocate for restoration of the upper Ventura River. Our main focus is a public outreach campaign to gain local, state, and national support for a multi-agency dam removal effort. Our strategy is to build the Coalition by linking government, science, and the community through a diversity of programs and activities, including direct participation in the decision-making process.

Current status: The Matilija Coalition has chosen a dam removal strategy! The official wording of this strategy, from Paul Jenkin’s Ventura River Ecosystem blogpost, is as follows:

The objective of this dam removal concept (DRC-2A) would be to erode and transport as much fine sediment as possible from the reservoir, while minimizing costs and time associated with large bypass/containment structure construction and sediment removal. The fine sediment mobilization would be achieved by allowing flow through two uncontrolled orifices, whose opening would be coordinated to coincide with a sufficiently high flow event[…]. The orifices are sized to pass the minimum high flow event in an unpressurized condition and are located to maximize mobilization of the reservoir sub-area sediments from the upstream face of the dam.

In simpler terms, we’re just gonna blow holes in that sucker!

Feasibility studies on the Matilija Dam along with the precedents set by other dam removals have demonstrated that this is a safe, effective, and relatively inexpensive way to clear the accumulated sediments and restore stream flow. Next steps include (1) secure funding and (2) perform necessary downstream improvements.

Artist’s conception of the upper river after the dam is gone.

For more information: Check out Paul Jenkin’s blog, Ventura River Ecosystem, which has detailed descriptions of the slow road to a freer Ventura River.